Human Nature
by magnyto
Summary: Illicit, unstable, choleric — life is turbulent and chaotic. And do not even begin to fathom the species that cannot and will not submit. Man is the only creature who refuses to be what he is. It was that simple for Sherlock Holmes. Sentiment was for children. That was until his life was thrust and intertwined with another. Sherlock/OC


**PART ONE:**

**Methods of Rationality**

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><p>"If I've said it once, I've said it a thousand times <em>—<em> my answer is _no." _

"That's a load of rubbish, Sherlock. Maybe I've only tried to talk you around to dating once or twice," John insisted as he fixed his collar on his shirt. "I can't help it if I don't particularly like seeing you cooped up in the flat all the time."

For the past week since John had scheduled a date with his current girlfriend of the month, he had been trying to persuade his flatmate to join him. John knew that Sherlock wasn't the most social person (oh Lord did he know because Sherlock certainly never let him forget that when he was snapping at one person or insulting another), but he didn't deserve to sit all day and stare at the embellished wallpaper or pluck sulky strings on his violin.

"I am not in it all the time. I do happen to go out, you know," Sherlock countered.

"Sure, for a walk or to hit the nearest pub. I'm talking about social interaction with other people beside me!"

"I'm not some recluse that when I do go in public, it needs to be celebrated like some sort off rare animal siting." Sherlock waved his hand. "This is London, not the Australian outback, and I am not a...a ruby crested _dingo_ or whatever they have below the equator."

"Ruby crested dingo?" John repeated in disbelief as he tried to stifle a wild laugh that threatened to burst forth from his lips. He rubbed his forehead in astonishment and paced the length of the room. "Jesus, Sherlock, this is almost as bad as the time you forgot that the Earth travels around the sun."

"You're never going to let me live that down, are you?" Sherlock sucked on the inside of his cheek and gave the doctor an eye roll.

"It's-it's _rudimentary!_"

"A lot of stuff that is rudimentary I really could care less about!" Sherlock exclaimed angrily, his dark curls bouncing in irritation. "Honestly, John, I thought you had figured this out by now."

John pinched the bridge of his nose. "Look, I'm sorry, I do know that but I just have a hard time understanding it."

Sherlock ignored him and straightened his shoulders. The consulting detective then shifted his gaze to his work before him.

John groaned. "Will you at least consider the offer?"

"Hmmm...anaphase." Sherlock pressed his eyes closer to the microscope and peered at the magnified specimen below him feigned interest.

"Remind me how we went from talking about dates to discussing genetics?"

"Cell division, John, this is basic mitosis. And you're the one talking about things that are rudimentary," he said with a slight grumble.

"What do you have against dating?!"

"It's _dull!" _

A silence thick with tension settled like a layer of dust across the flat. John buttoned up his shirt and studied his shoes while Sherlock finished observing the last mitosis slide and moved onto a cell undergoing meiotic prophase. The only sounds were the squeal of John shining his shoes and the sharp, annoyed exhale of Sherlock every time a squeak lasted longer than a few seconds.

Finally, John tried to defuse the tautness of the situation.

"Any new cases?"

"Yup," Sherlock said, popping the 'p'.

"Any worth investigating?"

Again, the younger of the two emphasized the 'p'. "Nope."

Sherlock listened as John shuffled into the kitchen and the fridge whooshed open. It was blissfully quiet until John heaved a sigh.

"I need to make grocery run," John announced.

Sherlock didn't respond as he watched the cellular movement unfold under the microscope. His ears picked up the ruffling rummage for cash and a mumbled grouch of a complaint.

"We really do need to find a case," John admitted. "I'm low."

John watched as Sherlock wrote down some notes on a scrap of paper beside him and went on with, "You want anything?"

Sherlock suppressed a biting retort. There were a lot of things he wanted but he didn't need to wound John's precious ego. Instead he snapped, "No."

"I'll pick up some milk then?"

At that moment the repetitious transition from slide to slide became too tedious to continue. Sherlock shoved his stuff aside and got to his feet, roughly scraping his chair across the floor and stomping over into the living room. Petulantly shoving the magazine across the coffee table with his feet as he stepped upon it, Sherlock slumped down onto the sofa, turned over with his back to John, and pulled his dressing gown around him while curling up into a ball.

"What are you, five?" John asked stroppily.

Sherlock's cross huff only confirmed his answer. John looked away and pursed his lips. He then rolled his eyes and left the flat without another word, slamming the door somewhat on his way out.

Angrily, the detective tugged the cushion under his head nearer to the back of the sofa and coiled even tighter. What did John know about dating? Most of his girlfriends didn't last more than a week or so on average. _'He had no right to lecture me,'_ Sherlock thought with a grimace. _'Besides, none of that nonsense even matters.'_

But all Sherlock could see was his first outing with John while they were investigating the Study in Pink Case. John's voice rang through his head loud and clear.

_"You don't have a girlfriend, then?"  
>"Girlfriend? No, not really my area."<br>"Mm...oh, right. D'you have a boyfriend? Which is fine, by the way."_

_"I know it's fine."  
>"So you've got a boyfriend then?"<br>"No."  
>"Right. Okay. You're unattached. Like me. Fine. Good." <em>

Everything was horrendously stupid. Caring was not an advantage. So why did he feel his heartstrings wrenching?

_"What do real people have, then, in their 'real lives'?"_  
><em>"Friends," <em>John had said simply. _"People they know; people they like; people they don't like...girlfriends, boyfriends..."_

Sherlock flailed angrily and wrapped his gown tighter around him as his toes kneaded the cushions. Sherlock had friends. He had John. John was his friend. And, the more he brewed over it, Molly was his friend too along with Mrs. Hudson and Lestrade. Weren't they all he needed? The Woman had just confused him. It was terribly hard to admit, but Sherlock _had _felt something for Irene, something he hadn't experienced in his life before. Every time his eyes had laid upon her, his heart skipped a beat. When he had first met her, her battle suit had frightened him at first (what suddenly naked woman wouldn't cause you to jump), but he hadn't been embarrassed by the nudity as John had. It was just a human body. He studied people for a living. So, Mycroft had been possibly correct. He did have some sediment for Irene but it wasn't anything he couldn't control. Love was for children. Emotion turned his brain to mush. The last thing he needed was his encephalon rotting because his pulse had been erratic around a female.

And, if John knew him so well, why did the doctor frequently insist he try dating (but maybe it wasn't so frequently, most of the time it was out of exasperation when Sherlock crashed one of his dates because he needed John to join him on a case and obviously John thought that if Sherlock had a significant other, they would join him on cases so John wouldn't have to run around all the time like a chicken with his head cut off, Sherlock deduced).

Did Sherlock know anything about people? No. Human nature? Of course not. If John relentlessly went on about something, it was muttered comments or looks of distaste when Sherlock did something incredibly _not _human.

Was that all he needed? To be more human?

'_Sediment is for children. Caring is not an advantage.' _Mycroft had drilled that much into Sherlock's skull. His brother was the one who was morally colder. _He _was the Iceman. Sherlock was getting better...wasn't he?

_"Don't be alarmed; it's to do with sex." _

God did Sherlock ever find his brother's sarcasm grating and obnoxious.

A solid sixty minutes later of moping that had seemed to Sherlock like only five, the consulting detective rolled off the couch and to his feet as elegantly as his entangled body would allow. He needed to get dressed and get out. The flat seemed to be closing in on him.

Once his trousers were on and his shirt was properly buttoned, Sherlock scooped up his coat and scarf from where he had cast it aside over the back of his chair. He donned his jacket, looped his scarf around his neck, and exited 221B in search for the London air.

The thrumming pulse of the city greeted him and Sherlock embraced it happily. The hustle and bustle of passing cars, pedestrians, and city folk allowed him to blend into the crowd which was just what he needed at that moment. It gave him time to think and straighten things out. Even though such a peace was distasteful (he would much rather be chasing a killer or have some sort of game to play with a suspect), he tried to not let it bother him too much.

The further he walked from his flat, the probability of coming across a crime soared. He pulled up a mental map of city. Perhaps he should take the west route...

The west route proved to be incredibly uninteresting. He hailed a taxi and told the driver to head to St. Bart's Hospital. Molly probably had a fresh stock of bodies to look at and autopsies to observe. She had been rambling enthusiastically how they had received a new shipment of scalpels. The thought was enough to entertain the bored genius for the time being.

He could do deductions.

The cabbie lived on his own — shaving cream behind the ear — and was single and unattached, had two great danes — brown and spotted hairs on his shirt — worked part time at a bar, had a dead father, didn't get along with his brother who had frequent affairs, recently laundered his clothes, and had spine issues on his lower and higher vertebra – hunched back and orthopedic shoes.

The woman who nearly bumped into him on the street after he had arrived regularly used Listerine, bleached her hair five different times for six different shades of red and blonde, had a tabby cat, and had recently broken up with her boyfriend because he wasn't "hardcore" enough for her.

The doctor in St. Bart's visited a house that is under work – sawdust in his hair and on his clothes – and had freshly showered with women's shampoo in a haste that morning. He didn't like his wife – the wedding band was on the wrong hand, was regularly removed and dirty, he was left handed, partially owned one, two, three, four, _five _cats that his wife and she kept adopting out of a lack of affection from him. He could tell by the five different cat hairs on his suit that he had three tabbies, a persian, and a siamese, and a small dog – a white one – from the stray hair on his sock. He wanted to be a lawyer but his parents wanted him to be a doctor.

Several bodies were displayed in the morgue and were covered from mid chest to ankles. Sherlock entered the morgue only to find Molly in mid demonstration to some of the new and younger workers. Their eyes found Sherlock immediately as he entered the room.

"Molly," Sherlock greeted. The woman turned to face the consulting detective with a smile of surprise.

"I'm not interrupting, am I?"

Molly's teeth skimmed her bottom lip and she pulled her goggles down around her neck. "Sort of. I was just trying to show how a basic autopsy here is preformed. Together we were going to figure out–"

"The cause of death?" Sherlock eyed the cadaver for a split second and pointed to his stomach. "Tumor in his lower abdomen. Pancreatic."

"Did you tell him, Ms. Hooper?" Miscellaneous Student No. 1 inquired.

Molly shook her head and fought to hold back a knowing smile. "No, I haven't. He can tell."

"We haven't even cut him open!" Miscellaneous Student No. 2 protested in a Scottish accent as he crossed his arms over his chest.

"It's obvious," Sherlock said. He found objections while he deduced tremendously irksome. "Slight bruising and protrusion on the skin from the expansion of the tumor. Now, if you don't mind, I was talking to _Ms. Hooper." _

Sherlock swiveled around to face Molly again and said, "I need some digits, specifically thumbs. Mrs. Hudson confiscated my last bag."

Molly nodded. "Working on a case?"

Before Sherlock could answer, the troublesome Miscellaneous Student No. 2 piped back up with an unnecessary opinion.

"Thumbs?" he griped. "What on Earth do you need thumbs for?"

Sherlock spun around and tried his best not to be livid. "It's for an experiment."

"What kind of nasty experiment would you need thumbs for?" the Scot questioned, his face puckered in disgust.

"I'm a consulting detective. To help with cases I sometimes need to do–"

"'Consulting detective'?! There's no such thing!"

Sherlock opened his mouth for a rather very nasty comment and to start embarrassing him by deductions but Molly grabbed him by the back of the collar and sent him out of the morgue with a bag of thumbs before he could even process what exactly had happened.

On the street again, Sherlock tried not to be angry. Even though the student had nearly set him off, he had what he had come for. Luckily he had some nitric acid left over from a few experiments ago. He could always nick some hydrochloric or sulfuric acid from the lab next time he went to Bart's, and, with Molly working there, he wouldn't get nicked himself.

Sherlock decided to walk back to his flat instead of taking a cab in a futile attempt to clear his head. Somedays it was a mental game of chess and, so far, the universe seemed to be besting him.

* * *

><p><strong>Continue Analysis?<strong>

_Yes. _

**Defect found; personal attachment. Continue anyway? **

The woman closed her eyes for a moment before entering in her response.

_Yes. _

**Analysis continued. **

Just as the first formula spiraled into existence, the female froze and took in a rattling breath. Her mind skidded to a grinding halt and she barely managed to crack open her eyes.

**Analysis delayed. Error detected; personal attachment. Continue? **

Her hands shook.

**Continue? **

**Continue? **

**Con- **

She logged off the mainframe, tremors shooting up her arms and to her spine from her balled hands.

The female took in a deep breath. She could see her shattered courage lying in fractured pieces at her feet. As she pressed her white knuckled fists to her eyes, she whispered, "Oh, pull it together, Elsie."

When her erratic heartbeat returned to its natural cadence, Elsie sucked in a gulp of air, smoothing down her jumper and trying not to panic every time her eyes darted to her surroundings. She could only imagine what had happened in the apartment. The brown-haired woman could hear her friends screams in the broken phone discarded on the floor and the rips in the drab carpeting, witness the brawl and frantic scramble in the tousled bedsheets and leaning door…

"No," she scolded with a sniff. "Stop. Don't do this to yourself."

Elsie left the tiny bedroom, escaping to the kitchen. She ignored the pictures on the fridge and gave her best attempt to stick to strictly logic.

Elsie couldn't help that her friend had a bad reputation. That wasn't the issue at hand. She had already tried to get the police involved — they had simply victim blamed and pointed fingers at Elsie's companion's past record, claiming she would be back in a week or so. She ran off often. It was common for her to jump from one place to another. But, the sight of the crime wasn't right. Things didn't add up. Her friend had hung up her old life and donned another; one more responsible.

It was then when Elsie pounded her hands on the table out of frustration with her situation that she spotted the newspaper under her palms. Between her fingers was a face of a man half hidden by a hat with another man covered by a different cap. The only features of the main man she could make out in the blurry, black and white photo was a pair of narrowed, yet bright, eyes perched above high cheekbones but resting below a head full of dark curls.

_Sherlock Holmes: The Enigma Himself_

Elsie moved her hands and slipped a piece of hair that had fallen out of her braid back behind her ear. She flipped open the paper and before she knew it, the mainframe had been revived.

_Sherlock Holmes was spotted once again outside of St. Bartholomew's after busting his last case. The genius, who has the self labeled occupation of a consulting detective — _

**Solution to current problem possibly found. More intel needed for the database. Research required. Conduct research?  
><strong>Elsie practically ripped her smartphone from her back pocket in her hasty excitement. She opened up a new tab on the internet and began to type.

**Input: Sherlock Holmes. Begin Analysis? **

_Begin._

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><p><strong>I have a lot of plans for this fic so I can only hope that you readers enjoy and this story will take off! <strong>


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